Recently, I've been having an issue where neither my Apple bluetooth Keyboard or Magic Trackpad pair automatically with the iMac at my password login screen. This forces me to hold down the power button and force a restart of the machine. Both accessories have plenty of battery power and pair fine after restarting. In a related problem, sometimes neither accessory will wake the iMac from sleep and I suspect it's because the bluetooth is dropping connection while asleep, thus making it impossible to wake up the iMac. Any ideas why this might be happening? Corrupt bluetooth .plist file? Or, could there be a problem with the iMac's built in bluetooth? Please let me know your thoughts.